The present invention relates to important improvements in highly advanced machine tools, and it particularly refers to a special head for machine tools, through which it is possible to place the single spindle provided thereon -- by means of an automatic control -- both in the horizontal and in the vertical position. The invention also relates to a machine tool equipped with said head and provided with a single device for automatically changing the tools on said spindle.
Machine tools comprising a single stationary spindle and means for automatically changing the tools on said spindle, have already been known for some time.
On the other hand, machine tools are also known to comprise two stationary orthogonal spindles, one being vertical and the other horizontal. In such machines, however, the change of the tools has so far not been automatic, due to the difficulty of having to mount simultaneously -- as would have been required -- two devices for the automatic change of the tools.
At present, one of the most felt requirements in this field -- which is in constant intensive development -- is hence to be able to dispose of a machine tool allowing to perform operations, both with a horizontal and with a vertical spindle, and allowing at the same time, to perform the automatic change of the tools.
The Applicant has faced this problem and has solved it in the most efficient way by drawing inspiration, partly from the already cited solutions of prior art, concerning volume production machine tools, and partly from a solution adopted in the past for machine tools of an entirely different type from that which the Applicant intended to realize, and meant for different purposes, that is, machine tools designed for the production, in single pieces and under the constant control of a skilled operator, of fixtures and the like. Some of these machines comprise a head in two parts, one of which, carrying the spindle, may be manually rotated in respect of the other -- which is fixed to the machine casing or to a slide thereof -- about an axis inclined by 45.degree. in respect of the working plane, and being perpendicular to the plane separating the two head parts, which is also inclined by 45.degree.. In such machine tools, the rotary part of the head carrying the spindle is moved manually by the operator so as to set the spindle in an infinite number of positions, between the vertical spindle position and the horizontal spindle position, hence allowing to choose the most appropriate positions for specific types of machining operations, as are required for the production of fixtures and the like.